The work proposed applies a new method developed by the PI to examine the stage of perceptual processing prior to recognition and depth perception, namely, the formation of perceptual units. The method uses depth ambiguity to assess the strength of the perceptual connection among various elements. Lines whose depth is resolved in common are assumed to be non-independent. The use of rotating lines allows us to measure the proportion of time during which this occurs for any set of elements. During the next year the emphasis will be on hemispheric and contextual effects on the formation of perceptual units and on teasing out subprocesses contributing to the effects obtained.